This invention relates to a disc cartridge, and more particularly to a disc cartridge having a disc-shaped medium such as an optical disc, a magneto-optical disc or the like received in a casing in a manner to be rotatable therein and removable therefrom for replacement.
In general, an information medium including, for example, a disc-shaped medium such as a magnetic disc, an optical disc, a magneto-optical disc or the like is used in the form of a disc cartridge while being received in a casing formed by joining upper and lower casing members to each other. The disc cartridge includes a shutter for selectively closing openings such as head insertion holes, drive shaft insertion holes and the like formed through the upper and lower casing members of the casing. In general, such a conventional disc cartridge is not provided with any means for taking out the disc-shaped medium from the casing for replacement. However, a disc cartridge called a CD caddie which is used for a CD-ROM or the like is constructed so as to permit a CD to be drawn out of a casing. Such a CD caddie is adapted to be used in a CD-ROM reproducing unit of the type of using the CD caddie. Thus, the disc-shaped medium is used either in the form as taken out from the disc cartridge or in the form as received in the disc cartridge depending on the type of a recording/reproducing unit, so that it is needed to take out the disc-shaped medium from the disc cartridge as required.
However, the conventional disc cartridge equipped with the disc-shaped medium takeout mechanism is not constructed so as to permit a shutter mechanism to be arranged on a side of the disc cartridge on which a disc-shaped medium takeout cover is arranged. Thus, the disc-shaped medium takeout mechanism fails to be applied to a disc cartridge of the type that openings such as head insertion holes, drive shaft insertion holes and the like are formed through an upper casing member and/or a lower casing member. (See Japanese Patent Application Laid-Open Publication No. 266669/1988.)
Another disc-shaped medium takeout mechanism is also proposed which is constructed so as to open only a side surface of the casing opposite to the shutter to take out the disc-shaped medium from the disc cartridge. The proposed disc-shaped medium takeout mechanism causes a disc-shaped medium takeout cover to be operated either detachably or pivotally. Detachable operation of the disc-shaped medium takeout cover leads to separation or removal of the cover from the casing, resulting in the cover being possibly lost. Pivotal operation of the cover causes it to be engaged with the casing through only pivot shafts, so that the cover, casing or pivot shafts may be broken due to application of shock or external force to the disc cartridge. Also, it fails to fully close the cover due to inclination thereof with respect to the casing, leading to a deterioration in reliability. (See Japanese Patent Application Laid-Open Publication No. 87677/1988.)
Further, the conventional disc cartridge of the type that the disc-shaped medium is taken out from the casing for replacement is constructed so as to take out the disc-shaped medium from the casing by gravity while keeping a disc-shaped medium takeout port of the casing downwardly directed or oriented. Thus, the disc cartridge encounters a common problem that careless or inadvertent disc taking-out operation by a user often causes accidental falling out or detachment of the disc from the casing.